The synthesis, processing and translocation of lysosomal enzymes are under continued investigation. 1) The Alpha- and Beta- chains of beta-hexosaminidase are synthesized in some cultured rodent cells as precursors of molecular weight about 14,000 higher than the mature chains; the precursor pieces may remain associated with the main chains by disulfide bonds. 2) The polypeptides of Beta-hexosaminidase synthesized by cells from patients with Mucolipidosis III are defective in that they are poorly phosphorylated and poorly processed. 3) The receptor-mediated uptake of Beta-galactosidase, another model lysosomal enzyme, proceeds via coated pits through uncoated vesicles, to coated vesicles in the Golgi/GERL region, and finally to lysosomes.